The Endless Installer for Windows creates a folder called C:\endless which will contain a file named endless.img for the Endless OS disk image. The files for the bootloader will be created in a subdirectory called grub. Do not delete the C:\endless folder without uninstalling Endless OS first or your computer may no longer start up.
The Endless Installer will edit policies to ensure better compatibility with Endless OS. It will do the following:
- Disable “fast boot” where Windows stores your computer’s memory to disk in order to boot up faster. This is because it prevents safe access to the computer’s C:\ drive from other operating systems, and Endless needs to access this drive to load its disk image.
- Set Windows to store the computer’s time in UTC rather than your local time zone. This is to avoid problems with Endless OS and Windows not knowing whether the other OS has updated the computer’s clock with daylight savings time.
The Endless Installer will install the GRUB bootloader to your computer so that it shows a menu option at startup to either boot Endless OS or Windows:
In the case of UEFI boot, we also install the “shim” bootloader which is required for Secure Boot and set this as the default, and it loads GRUB after validating the signature. These bootloaders are stored in your computer’s ESP (EFI Service Partition) rather than your C:\ drive.
In the case of BIOS boot:
- If you originally installed Endless OS 3.2 or newer, we install GRUB to C:\eosldr and a small chain loader (which locates and executes GRUB) to C:\eosldr.mbr. We then configure the Windows boot menu to have a 30-second timeout and add an Endless OS entry pointing to C:\eosldr.mbr.
- If you originally installed an older version, we install GRUB to the MBR (master boot record) at the start of your hard drive, and to space after it (the “boot track”) before the first partition. This loads the rest of the GRUB bootloader from C:\endless\grub.